JP2018081007A - Radar device and target detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device and a target detection method with which it is possible to track a target which could be a pedestrian continuously for a longer time.SOLUTION: A radar device according to an embodiment comprises a detection unit, an extrapolation unit, a count unit, a determination unit and an adjustment unit. The detection unit repeatedly performs detection of a target approaching the own vehicle. The extrapolation unit performs an extrapolation process for predicting on the basis of the previous detection result a virtual position of the target that was not detected by the latest detection. When a target is detected, the count unit adds a fixed value to the count value that indicates the level of possibility that the target is present; when not detected, the count unit subtracts a prescribed value from the count value. The determination unit determines the level of possibility that the target is a pedestrian on the basis of the lateral movement speed, lateral movement amount and lateral position variation of a target present out of a prescribed angle range from the own vehicle. When the target is the object of the extrapolation process, the adjustment unit adjusts a value subtracted from the count value in correspondence to the level of possibility of being a pedestrian.SELECTED DRAWING: Figure 1D

Description

  Embodiments disclosed herein relate to a radar apparatus and a target detection method.

  Conventionally, a transmission wave transmitted from the host vehicle receives a reflected wave reflected by the target, and a target approaching the host vehicle is continuously detected by repeating detection processing for detecting the target based on the received reflected wave. There is a radar device to detect. In general, a radar apparatus detects a target that exists within a predetermined angle range such that a reflected wave exceeding a certain level with respect to a transmission wave from the radar apparatus can be obtained with reference to the traveling direction of the host vehicle (for example, Patent Document 1).

JP 2012-013484 A

  However, in the conventional radar apparatus, when the target is outside the predetermined angle range, the signal detection level of the reflected wave is below a certain level, so that the detection accuracy of the target is lowered. For example, when a pedestrian crossing a road on which the vehicle is traveling is outside a predetermined angle range, it may be difficult to detect such a target that may be a pedestrian.

  That is, when a pedestrian crossing the road moves from within a predetermined angle range to outside the predetermined angle range, within the predetermined angle range, the radar device continuously detects a target related to the pedestrian, After moving outside the predetermined range, it is difficult to detect a target that may be a pedestrian. As a result, it may be difficult for the radar apparatus to track a target that may collide with the vehicle.

  One aspect of the embodiments is made in view of the above, and provides a radar apparatus and a target detection method capable of continuously tracking a target that may be a pedestrian for a longer time. With the goal.

  A radar apparatus according to an aspect of an embodiment includes a detection unit, an extrapolation unit, a count unit, a determination unit, and an adjustment unit. The detection unit repeatedly performs a detection process for detecting a target approaching the host vehicle. The extrapolation unit performs an extrapolation process for predicting a virtual position of the target that is no longer detected in the current detection process based on the target detected in the previous detection process. Each time the target is detected by the detection process, the count unit adds a fixed value to a count value indicating a high possibility that the target exists, and the virtual part of the target is added by the extrapolation process. Each time a position is predicted, a predetermined value is subtracted from the count value of the target. The determination unit is based on a lateral movement speed of the target existing outside the predetermined angle range with respect to the traveling direction of the host vehicle, the lateral movement amount, and the lateral position variation. Then, it is determined whether the target is likely to be a pedestrian. The adjustment unit, when a target that exists outside the predetermined angle range is the target of the extrapolation process, according to the height of the possibility determined by the determination unit, the count of the target The predetermined value to be subtracted from the value is adjusted.

  According to the radar device and the target detection method according to one aspect of the embodiment, a target that may be a pedestrian can be continuously tracked for a longer time.

FIG. 1A is an explanatory diagram of a target detection method according to an embodiment. FIG. 1B is an explanatory diagram of the target detection method according to the embodiment. FIG. 1C is an explanatory diagram of the target detection method according to the embodiment. FIG. 1D is an explanatory diagram of the target detection method according to the embodiment. FIG. 2 is a block diagram illustrating the radar apparatus according to the embodiment. FIG. 3A is an explanatory diagram of processing from pre-processing in the signal processing device according to the embodiment to peak extraction processing in the signal processing device. FIG. 3B is an explanatory diagram of processing from pre-processing in the signal processing device according to the embodiment to peak extraction processing in the signal processing device. FIG. 3C is an explanatory diagram of processing from pre-processing of the signal processing device according to the embodiment to peak extraction processing in the signal processing device. FIG. 4A is a process explanatory diagram of the azimuth calculation process according to the embodiment. FIG. 4B is a process explanatory diagram (part 1) of the pairing process according to the embodiment. FIG. 4C is a process explanatory diagram (part 2) of the pairing process according to the embodiment. FIG. 5 is a block diagram illustrating a count processing unit according to the embodiment. FIG. 6 is an explanatory diagram illustrating an example of pedestrian condition information according to the embodiment. FIG. 7A is an explanatory diagram of count value adjustment area information according to the embodiment. FIG. 7B is an explanatory diagram of count value adjustment area information according to the embodiment. FIG. 7C is an explanatory diagram of count value adjustment area information according to the embodiment. FIG. 8 is an explanatory diagram illustrating an example of count value adjustment information according to the embodiment. FIG. 9 is an explanatory diagram of the operation of the count processing unit according to the embodiment. FIG. 10 is a flowchart illustrating main processing executed by the data processing unit of the radar apparatus according to the embodiment. FIG. 11 is a flowchart showing the counting process during the main process according to the embodiment. FIG. 12 is an explanatory diagram illustrating an example of pedestrian condition information stored in the radar device according to the first modification of the embodiment. FIG. 13 is an explanatory diagram of a procedure in which the radar device according to the first modification of the embodiment determines the degree of coincidence between the position of the target and the predicted movement miracle of the pedestrian. FIG. 14 is an explanatory diagram illustrating an example of count value adjustment information stored in the radar apparatus according to Modification 1 of the embodiment. FIG. 15 is an explanatory diagram illustrating an example of pedestrian condition information stored in the radar device according to the second modification of the embodiment.

  Hereinafter, embodiments of a radar apparatus and a target detection method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  First, a target detection method performed by the radar apparatus according to the embodiment will be described with reference to FIGS. 1A, 1B, 1C, and 1D. 1A, 1B, 1C, and 1D are explanatory diagrams of a target detection method according to an embodiment. Here, the case where a radar apparatus is provided in the center of the front grille of the own vehicle C is demonstrated.

  Note that the position where the radar device is provided is not limited to this, and may be an arbitrary position such as a rear portion, a side surface, or a rearview mirror of the host vehicle C. Hereinafter, the traveling direction of the host vehicle C may be referred to as a vertical direction, and the direction intersecting the traveling direction of the host vehicle C may be referred to as a lateral direction.

  As shown in FIG. 1A, the radar apparatus according to the embodiment includes a target TG that exists in an area within a predetermined angle range based on the traveling direction of the host vehicle C (hereinafter referred to as “detectable area A”). Is detected. Such a radar device continuously detects the target TG in the detectable area A by repeating detection processing for detecting a target approaching the host vehicle C.

  Further, the radar device moves the virtual position of the target TG to the previous time when the target TG is outside the detectable area A as the target TG approaches and the target TG is not detected by the current detection process. An extrapolation process for predicting based on the target TG detected in the detection process is performed.

  Further, every time the target TG is detected by the detection process, the radar apparatus adds a fixed value to the count value indicating the high possibility that the target TG exists, and performs an extrapolation process on the virtual TG of the target TG. Every time the position is predicted, a count process is performed to subtract a predetermined value from the count value of the target TG.

  Then, when the count value of the target TG becomes a threshold value (for example, 0) or less, the radar apparatus detects a specific target (hereinafter referred to as a pedestrian or the like) that may collide with the target vehicle TG. , And described as “specific target”) (hereinafter simply referred to as “tracking target”). For example, the radar device deletes information related to the target stored in the storage unit included in the radar device.

  In FIG. 1A, for a target TG that gradually approaches the host vehicle C from the vertical direction, the target TG at the time when the count value is larger than the threshold value is indicated by a white circle, and the object at the time when the count value becomes less than or equal to the threshold value. The mark TG is indicated by a black circle. Thus, even if the target TG is outside the detectable area A, the radar device can continuously detect the target TG until the count value of the target TG becomes equal to or less than the threshold value.

  Here, when the target TG outside the detectable area A is a roadside object such as a guardrail, the radar apparatus collides with the own vehicle C as long as the own vehicle C is traveling along the road. There is no problem even if it is excluded from the tracking target at a relatively early time.

  However, when the target TG outside the detectable area A is a pedestrian, the radar apparatus may collide with the host vehicle C by crossing the road (for example, jumping out). For this reason, it is desirable for the radar apparatus 1 to track a target that may be a pedestrian crossing the road for as long a time as possible even outside the predetermined angle range.

  Therefore, the radar device uses the difference between the behavior characteristics of the target TG other than the pedestrian and the behavior characteristics of the pedestrian, and the possibility that the target TG outside the detectable area A is a pedestrian. The predetermined value to be subtracted from the count value of the target TG is adjusted according to the determined possibility height.

  Specifically, as shown in FIG. 1B, for example, a roadside object such as the guard rail TG1 does not change in the lateral distance between the host vehicle C and the host vehicle C even when the host vehicle C travels. That is, roadside objects such as the guardrail TG1 are characterized in that they hardly move in the lateral direction intersecting the traveling direction of the host vehicle C when viewed from the host vehicle C. Further, for example, a downward object such as a manhole or a so-called ghost that is not actually present but is erroneously detected due to noise or the like hardly moves in the lateral direction when viewed from the own vehicle C.

  On the other hand, as shown in FIG. 1C, a pedestrian P that crosses the road on which the host vehicle C travels becomes a pedestrian P that may collide with the host vehicle C. The direction distance gradually decreases. That is, the pedestrian P is characterized by moving in a lateral direction intersecting with the traveling direction of the host vehicle C when viewed from the host vehicle C.

  Therefore, the radar apparatus determines whether the target TG is based on the lateral movement speed V of the target TG outside the detectable area A with respect to the host vehicle C, the lateral movement amount L1, and the lateral position variation L2. The high possibility of being a pedestrian that collides with the host vehicle C is determined. Then, the radar apparatus adjusts a predetermined value to be subtracted from the count value of the target TG according to the determined possibility of being a pedestrian.

  Here, with reference to FIG. 1D, an example in which the radar apparatus adjusts the value to be subtracted from the count value according to the high possibility of a pedestrian will be described. Note that the target TG2 indicated by white circles and black circles in FIG. 1 is, for example, a roadside object such as a signboard installed on the side of the road on which the host vehicle C travels. A white circle indicates a position at each time point when the count value of the target TG2 is larger than the threshold value, and a black circle indicates a position at a time point when the count value of the target TG2 is equal to or less than the threshold value.

  In addition, the target TG3 indicated by the white square and the black square in FIG. It is. The white square indicates the position at each time point when the count value of the target TG3 is greater than the threshold value, and the black square indicates the position when the count value of the target TG3 is equal to or less than the threshold value.

  In addition, a target T4 indicated by a white triangle and a black triangle in FIG. 1D is a pedestrian who has a high possibility of colliding with the host vehicle C, such as crossing a road on which the host vehicle C travels. The white triangle indicates the position at each time point when the count value of the target TG4 is greater than the threshold value, and the black triangle indicates the position when the count value of the target TG4 is less than or equal to the threshold value.

  As shown in FIG. 1D, when the target TG2 indicated by the white circle is outside the detectable area A, the radar device does not move in the horizontal direction and the lateral position variation is large. It is determined that the possibility of being a pedestrian is low.

  In such a case, the radar apparatus subtracts a predetermined maximum value from the count value of the target TG2 in one count process. Thereby, for example, as indicated by a black circle in FIG. 1D, the radar apparatus excludes the target TG2 from the tracking target in the fourth counting process after the area A is out of the detectable area A.

  Further, when the target TG3 indicated by the white square is outside the detectable area A, the radar apparatus has a slight variation in the lateral position of the target TG3, but the target TG3 moves in the horizontal direction at a speed equivalent to walking. Since it is moving, it is determined that the possibility of a pedestrian is higher than the target TG2 indicated by a white circle.

  In such a case, the radar apparatus makes the value subtracted from the count value of the target TG3 in one count process smaller than the target TG2 indicated by a white circle. Thereby, for example, as shown by a black square in FIG. 1C, the radar apparatus excludes the target TG3 from the tracking target in the seventh count process after the outside of the detectable area A.

  Therefore, the radar apparatus can continuously track the target TG3 indicated by a white square with a possibility of a pedestrian for a longer time than the target TG2 indicated by a white circle with a low possibility of a pedestrian.

  In addition, when the target TG4 indicated by the white triangle is outside the detectable area A, the radar apparatus has a lateral movement speed and distance of the target TG4 that exceeds the target TG3 indicated by the white square. Since the variation is small, it is determined that the possibility of a pedestrian is higher than the target TG3 indicated by the white square.

  In such a case, the radar apparatus makes the value to be subtracted from the count value of the target TG4 in one count process smaller than that of the target TG3 indicated by a white square. Thereby, for example, as shown by a black triangle in FIG. 1D, the radar apparatus excludes the target TG4 from the tracking target in the tenth count processing after the area A is out of the detectable area A.

  Therefore, the radar apparatus can track a target TG4 indicated by a white triangle, which is likely to be a pedestrian, as a specific target continuously for a longer time than the target TG3 indicated by a white square.

  Next, the configuration of the radar apparatus 1 according to the embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating the radar apparatus 1 according to the embodiment. In FIG. 2, only components necessary for explaining the features of the present embodiment are represented by functional blocks, and descriptions of general components are omitted.

  In other words, each component illustrated in FIG. 2 is functionally conceptual and does not necessarily need to be physically configured as illustrated. For example, the specific form of distribution / integration of each functional block is not limited to the one shown in the figure, and all or a part thereof is functionally or physically distributed in arbitrary units according to various loads or usage conditions.・ It can be integrated and configured.

  As shown in FIG. 2, the radar apparatus 1 includes a transmission unit 2 and a transmission antenna 4 as components that constitute a transmission system. The transmission unit 2 includes a signal generation unit 21 and an oscillator 22.

  In addition, the radar apparatus 1 includes reception antennas 5-1 to 5-n and reception units 6-1 to 6-n as components constituting the reception system. Each of the reception units 6-1 to 6-n includes a mixer 61 and an A / D conversion unit 62. The radar apparatus 1 includes a signal processing device 7 as a component constituting the signal processing system.

  In the following, for the sake of simplification of explanation, when “reception antenna 5” is simply described, the reception antennas 5-1 to 5-n are collectively referred to. The same applies to the “receiving unit 6”.

  The transmission unit 2 performs processing for generating a transmission signal. The signal generation unit 21 generates a modulation signal for transmitting a millimeter wave that is frequency-modulated with a triangular wave, under the control of a transmission / reception control unit 71 provided in the signal processing device 7 described later. The oscillator 22 generates a transmission signal based on the modulation signal generated by the signal generation unit 21.

  The transmission antenna 4 transmits the transmission signal generated by the oscillator 22 as a transmission wave in front of the host vehicle C. As shown in FIG. 2, the transmission signal generated by the oscillator 22 is also distributed to the mixer 61 described later.

  The reception antenna 5 receives the reflected wave coming from the target as a reception signal by reflecting the transmission wave transmitted from the transmission antenna 4 on the target. Each of the reception units 6 performs pre-processing until each received signal is passed to the signal processing device 7.

  Specifically, each of the mixers 61 mixes the transmission signal distributed as described above and the reception signal received at each of the reception antennas 5 to generate a beat signal. A corresponding amplifier may be provided between the receiving antenna 5 and the mixer 61.

  The A / D converter 62 digitally converts the beat signal generated in the mixer 61 and outputs it to the signal processing device 7. The signal processing device 7 includes a transmission / reception control unit 71, an FFT (Fast Fourier Transform) unit 72, a data processing unit 73, and a storage unit 74.

  The data processing unit 73 includes, for example, a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output port, and various circuits.

  The data processing unit 73 includes a plurality of processing units that function when the CPU executes the target detection program stored in the ROM using the RAM as a work area. Specifically, the data processing unit 73 includes a peak extraction unit 73a, an azimuth calculation unit 73b, a pairing unit 73c, a continuity determination unit 73d, a filter processing unit 73e, a count processing unit 73f, a target classification unit 73g, an unnecessary object. A target determination unit 73h, a combination processing unit 73i, and an output target selection unit 73j are provided.

  Each or all of the processing units included in the data processing unit 73 may be configured by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

  The storage unit 74 is a storage device such as a hard disk drive, a nonvolatile memory, or a register, and stores pedestrian condition information 74a, count value adjustment area information 74b, count value adjustment information 74c, and a count value 74d.

  The pedestrian condition information 74a is information that the data processing unit 73 refers to when determining the rank indicating the high possibility that the target is a pedestrian (hereinafter referred to as “pedestrian possibility rank”). It is. An example of the pedestrian condition information 74a will be described later with reference to FIG.

  The count value adjustment area information 74b is information indicating an area in which the data processing unit 73 adjusts a value to be subtracted from the count value of the target in the count process described later. An example of the count value adjustment area information 74b will be described later with reference to FIGS. 7A to 7C.

  The count value adjustment information 74c is information that is referred to when the data processing unit 73 adjusts a value to be subtracted from the target count value in a count process described later. An example of the count value adjustment information 74c will be described later with reference to FIG.

  The transmission / reception control unit 71 controls the transmission unit 2 including the signal generation unit 21 described above. Further, although not shown, the control of each receiving unit 6 is also performed. The FFT unit 72 performs fast Fourier transform on the beat signal input from each A / D conversion unit 62 and outputs the result to the peak extraction unit 73 a of the data processing unit 73.

  The peak extraction unit 73a extracts a peak frequency that becomes a peak in the fast Fourier transform result by the FFT unit 72 and outputs the peak frequency to the azimuth calculation unit 73b. The peak extraction unit 73a extracts a peak frequency for each of an “UP section” and a “DN section” of a beat signal to be described later.

  The azimuth calculation unit 73b calculates the arrival angle of the reflected wave corresponding to each of the peak frequencies extracted by the peak extraction unit 73a and its signal intensity (reception level). At this time, the arrival angle includes the case where the phase is turned back and is an angle at which the target is estimated to exist. In addition, the azimuth calculation unit 73b outputs the calculated estimated angle and reception level to the pairing unit 73c.

  The pairing unit 73c determines the correct combination of the peak frequencies of the “UP section” and the “DN section” based on the calculation result of the azimuth calculation unit 73b, and calculates the distance and relative speed of each target from the combination result. . The pairing unit 73c outputs information including the estimated angle, distance, and relative speed of each target to the continuity determination unit 73d.

  Here, the flow of a series of processes so far in the signal processing device 7 will be described with reference to FIGS. 3A, 3B, 3C, 4A, 4B, and 4C. 3A, 3B, and 3C are explanatory diagrams of processing from the previous stage processing of the signal processing device 7 to the peak extraction processing in the signal processing device 7 according to the embodiment.

  FIG. 4A is a process explanatory diagram of the azimuth calculation process according to the embodiment. FIG. 4B is a process explanatory diagram (part 1) of the pairing process according to the embodiment. FIG. 4C is a process explanatory diagram (No. 2) of the pairing process according to the embodiment.

  As shown in FIG. 3A, the transmission signal fs (t) is transmitted from the transmission antenna 4 as a transmission wave, then reflected by the target and arrives as a reflection wave, and received at the reception antenna 5 as a reception signal fr (t). Received.

  At this time, as shown in FIG. 3A, the reception signal fr (t) is delayed by a time difference τ with respect to the transmission signal fs (t) according to the distance between the host vehicle C and the target. Due to this time difference τ and the Doppler effect based on the relative speed of the host vehicle C and the target, the frequency increases in the output signal obtained by mixing the reception signal fr (t) and the transmission signal fs (t). A beat signal is obtained in which the frequency “up” of the “UP section” and the frequency fdn of the “DN section” where the frequency decreases are repeated.

  FIG. 3B schematically shows the result of fast Fourier transform of the beat signal in the FFT unit 72 for the “UP section” side. FIG. 3C schematically shows the result of fast Fourier transform of the beat signal in the FFT unit 72 for the “DN section” side.

  As shown in FIGS. 3B and 3C, after the fast Fourier transform, waveforms in the respective frequency domains on the “UP section” side and the “DN section” side are obtained. The peak extraction unit 73a extracts a peak frequency at which the signal intensity has a maximum value (peak) in the waveform.

  For example, in the case of the example shown in FIG. 3B, the peak extraction threshold is used, the peaks Pu1 to Pu3 are determined as peaks on the “UP section” side, and the peak frequencies fu1 to fu3 are extracted, respectively.

  Further, as shown in FIG. 3C, on the “DN section” side, the peaks Pd1, Pd2, and Pd3 are determined as peaks by the peak extraction threshold, and the peak frequencies fd1, fd2, and fd3 are extracted.

  Here, the frequency component of each peak frequency extracted by the peak extraction unit 73a may be a mixture of reflected waves from a plurality of targets. Therefore, the azimuth calculation unit 73b performs azimuth calculation for each peak frequency and analyzes the presence of a target corresponding to each peak frequency.

  Note that the azimuth calculation in the azimuth calculation unit 73b is performed using a predetermined arrival direction estimation method such as ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques), but is not limited thereto.

  FIG. 4A schematically shows the result of the azimuth calculation performed by the azimuth calculation unit 73b. The azimuth calculation unit 73b calculates an estimated angle of each target corresponding to each of the peaks Pu1 to Pu3 from the peaks Pu1 to Pu3 of the azimuth calculation result. Moreover, the magnitude | size of each peak Pu1-Pu3 becomes a reception level. The azimuth calculation unit 73b performs the azimuth calculation processing on each of the “UP section” side and the “DN section” side.

  At this time, for example, when the estimated angle of the target with respect to the radar apparatus 1 exceeds the detectable angle, the azimuth calculation unit 73b may cause the phase difference between the reception signals received by the adjacent reception antennas to exceed 360 °. .

  In such a case, the azimuth calculation unit 73b may, for example, set the estimated angle of the target that is actually β ° left (outside) from one of the left detectable angles to β ° May be calculated as left side (inside). Thus, the phase wrapping described above occurs.

  As shown in FIG. 4B, the pairing unit 73c performs pairing that combines the peaks with the estimated angles and the reception levels close to each other in the azimuth calculation result of the azimuth calculation unit 73b. Further, from the combination result, the pairing unit 73c calculates the distance and relative velocity of each target corresponding to each peak combination. The distance is calculated based on the relationship of “distance ∝ (fup + fdn)”. The relative speed is calculated based on the relationship of “speed ∝ (fup−fdn)”.

  Thus, as shown in FIG. 4C, the pairing unit 73c obtains a pairing processing result indicating the estimated angle, distance, and relative speed of each target TG with respect to the host vehicle C, thereby detecting each target TG. Process. And the pairing part 73c outputs the pairing process result used as a detection process result to the continuity determination part 73d.

  As described above, the peak extraction unit 73a, the azimuth calculation unit 73b, and the pairing unit 73c function as a detection unit that detects a target approaching the host vehicle C by performing the series of processes described above.

  Returning to the description of FIG. 2, the continuity determination unit 73d will be described. The continuity determination unit 73d determines whether or not the instantaneous value of the target being determined by the current detection process has continuity with the target detected by the previous detection process.

  Specifically, the current predicted position is calculated from the position of the target up to the previous detection process, and if there is an instantaneous value close to the predicted position in the current detection process, it is determined that the instantaneous value has continuity. . Then, the continuity determination unit 73d outputs information on the target after the continuity determination to the filter processing unit 73e.

  The filter processing unit 73e is a processing unit that corrects variation in instantaneous values for each target by a filtering process that averages the instantaneous values for a plurality of times processed in time series. Further, when there is no instantaneous value close to the predicted position in the current detection process as a result of the continuity determination, the filter processing unit 73e detects the current detection based on the instantaneous value of the same target detected in the previous detection process. An extrapolation process for predicting a virtual position or the like of a target that is no longer detected in the process is performed.

  Here, the filter processing unit 73e is configured to virtually calculate the vertical position that is the distance in the vehicle traveling direction between the target and the host vehicle C, and the horizontal position in the vehicle width direction, or the target and the host vehicle. A virtual relative speed obtained by virtually calculating a relative speed with C is predicted. In the following description, a virtual position will be described as an example among the virtual position and virtual relative speed derived by extrapolation processing.

  As described above, when there is no instantaneous value close to the predicted position in the current detection process, the filter processing unit 73e detects the virtual position of the target that is no longer detected in the current detection process and the target detected in the previous detection process. Functions as an extrapolation unit that performs extrapolation processing based on the above.

  The filter processing unit 73e outputs information on the target after the filtering process to the target classification unit 73g. Further, the filter processing unit 73e outputs information on the target after the filter processing to the count processing unit 73f.

  The count processing unit 73f is a processing unit that counts a count value 74d that indicates the possibility that the target detected this time exists and stores the count value 74d in the storage unit 74. When the target is detected by the current detection process, the count processing unit 73f adds a certain value (for example, 4) to the count value 74d of the detected target each time. The count value 74d is provided with an upper limit value (for example, 35) in advance.

  In addition, the count processing unit 73f is not detected by the current detection process, and each time the virtual position of the target is predicted by the extrapolation process, the count processing unit 73f uses the target count value 74d for which the virtual position is predicted. A predetermined value is subtracted. A target whose count value 74d has become equal to or smaller than a threshold (for example, 0) by subtraction is excluded from the tracking target by the unnecessary target determination unit 73h in the subsequent stage.

  When the count processing unit 73f subtracts a predetermined value from the count value 74d, the count processing unit 73f first determines the pedestrian possibility ranking for the target to be subtracted. Then, the count processing unit 73f adjusts a predetermined value to be subtracted from the count value 74d according to the determined pedestrian possibility ranking, thereby continuing a target that may be a pedestrian for a longer time. Can be traced.

  Here, the count processing unit 73f will be described in more detail with reference to FIGS. FIG. 5 is a block diagram illustrating the count processing unit 73f according to the embodiment. FIG. 6 is an explanatory diagram showing an example of pedestrian condition information 74a according to the embodiment.

  7A to 7C are explanatory diagrams of the count value adjustment area information 74b according to the embodiment. FIG. 8 is an explanatory diagram showing an example of the count value adjustment information 74c according to the embodiment. FIG. 9 is an explanatory diagram of the operation of the count processing unit 73f according to the embodiment.

  As illustrated in FIG. 5, the count processing unit 73f includes a determination unit 75a, an adjustment unit 75b, and a count unit 75c. The determination unit 75a determines whether or not the target detected this time is in the detectable area A based on the estimated angle of the target after filtering input from the filter processing unit 73e.

  Here, the traveling direction of the host vehicle C is assumed to be 0 [deg], and an angular range of 15 [deg] on the left and right with respect to the traveling direction of the host vehicle C will be described as the detectable area A. If the determination unit 75a determines that the target detected this time is within the detectable area A, the determination unit 75a outputs information indicating that fact to the count unit 75c.

  When the information indicating that the target is in the detectable area A is input from the determination unit 75a, the count unit 75c adds a certain value (for example, 4) to the count value 74d of the target detected this time. And stored in the storage unit 74.

  In addition, when the determination unit 75a determines that the target detected this time is outside the detectable area A, the estimated angle, distance, relative speed, and the post-filter target input from the filter processing unit 73e, and Based on the pedestrian condition information 74a, the pedestrian possibility ranking of the target is determined.

  Specifically, the determination unit 75a first determines the horizontal movement speed, the horizontal movement amount, and the horizontal position of the target based on the estimated angle, distance, and relative speed of the target sequentially input from the filter processing unit 73e. Calculate the variation.

  Here, the lateral movement speed is a movement speed of the target in the lateral direction intersecting the traveling direction (vertical direction) of the host vehicle C. The lateral movement amount is the lateral movement amount from the position where the target starts moving in the horizontal direction to the position where the target is detected this time.

  Further, the lateral position variation is a lateral position variation of the target with respect to the host vehicle C. Specifically, when the radar apparatus 1 sequentially repeats the process of detecting and tracking the same target, it is ideal to receive the reflected wave from the same reflection point on the same target every time the process is performed. is there.

  However, the radar apparatus 1 may receive reflected waves from different reflection points on the same target for each processing depending on the shape of the target, and in such a case, a position different from the position where the target has actually moved. May be determined as the position of the target.

  For example, when the target is a pedestrian, the reflection points such as hands, torso, and feet vary, but the variation is smaller than that of an object such as a vehicle. Since the vehicle has a body width of about 2 m, the variation may be relatively large.

  Therefore, in the present embodiment, the variation in the lateral position of the same target detected by the radar apparatus 1 with respect to the host vehicle C due to the variation in the reflection point of the same target is defined as the lateral position variation.

  Subsequently, for each of the calculated lateral movement speed, lateral movement amount, and lateral position variation of the target, the determination unit 75a includes the first condition, the second condition, and the second condition included in the pedestrian condition information 74a illustrated in FIG. It is determined whether or not the third condition is established, and the pedestrian possibility ranking of the target is determined.

  As shown in FIG. 6, in the pedestrian condition information 74a, condition contents and weighting information are associated with the first condition, the second condition, and the third condition, respectively. This is information associated with a pedestrian possibility ranking.

  In FIG. 6, “◯” means that the condition is satisfied, and “X” means that the condition is not satisfied. As shown in the figure, the first condition is a condition that the lateral movement speed is 2.3 [km / h] or more, which is an example of the first threshold. The first condition is a condition that the target is moving in the lateral direction (direction intersecting the direction in which the host vehicle C travels) at a speed equivalent to that of walking.

  The second condition is that the absolute value of the value obtained by subtracting the current horizontal position from the movement start horizontal position of the target, that is, the horizontal movement amount of the target is 2.5 [m] as an example of the second threshold value. This is the condition. The second condition is a condition that the target does not move laterally such as roadside objects, ghosts, and lower objects.

  The third condition is a condition that the lateral position variation is within 1.0 [m], which is an example of the third threshold value. The third condition is a condition that the lateral position variation of the target is within the movable range of the pedestrian's limbs during a general walking motion.

  That is, for example, this condition is determined so that the target determined to have moved in one of the horizontal directions (for example, the right direction) in the previous processing has returned to the left in the current processing. If the difference in the current lateral position moved to the left from the previous lateral position is within 1.0 [m], compared to a target with a relatively large variation in other vehicles, etc. If the variation is relatively small, it is a condition for determining a target.

  Specifically, the pedestrian's hand (right hand) moved rightward is the reflection point last time, and the pedestrian's foot (left hand movement) moved rightward is the reflection point this time. This is a condition for determining a target with high possibility of a pedestrian.

  Then, the determination unit 75a determines the pedestrian possibility ranking as the number of established first condition, second condition, and third condition for the calculated lateral movement speed, lateral movement amount, and lateral position variation increases. Is determined to be high.

  Specifically, the determination unit 75a determines the highest pedestrian possibility ranking of a target that satisfies all three conditions of the first condition, the second condition, and the third condition as “1”. In addition, the determination unit 75a determines that the pedestrian possibility ranking of a target in which all of the three conditions of the first condition, the second condition, and the third condition are not satisfied is the lowest “7”.

  As described above, the determination unit 75a determines that the pedestrian possibility ranking is higher as the number of established conditions of the first condition, the second condition, and the third condition using the characteristics of the pedestrian behavior increases. Thus, it is possible to accurately determine the possibility that the target is a pedestrian.

  In addition, when the number of established conditions is the same, the determination unit 75a determines the pedestrian possibility ranking based on the weighting information assigned to the established condition among the first condition, the second condition, and the third condition. Determine.

  The weighting information is information indicating the level of importance of the first condition, the second condition, and the third condition in the determination of the pedestrian possibility ranking. Here, the determination of the lateral movement amount as the second condition and the lateral position variation as the third condition requires at least two or more processes in time series for the same target. On the other hand, the lateral movement speed, which is the first condition, can be determined early in one process based on the instantaneous value of the target. For this reason, in this embodiment, as shown in FIG. 6, “3” having the highest importance is assigned to the first condition.

  Further, the lateral movement speed that is the first condition and the lateral movement amount that is the second condition are materials for determining whether or not the target is moving in a lateral direction that may collide with the host vehicle C. On the other hand, as described above, the lateral position variation of the third condition is mainly used to determine whether the target is a pedestrian or a target such as a vehicle having a wider width than the pedestrian. It is not a material for determining whether or not the target is moving in a lateral direction that may collide with the host vehicle C.

  For this reason, as shown in FIG. 6, in this embodiment, “2” having the second highest degree of importance is assigned to the second condition, and the lowest degree of importance is assigned to the third condition. Assign “1”. Thereby, the determination part 75a can determine with a pedestrian possibility order | rank being so high that the conditions with high importance in the determination of a pedestrian possibility order | rank are satisfied.

  Here, the combination in which two conditions are satisfied among the first condition, the second condition, and the third condition is satisfied when the first condition and the second condition are satisfied, and when the first condition and the third condition are satisfied. There are three cases: the case and the second condition and the third condition.

  The sum of the weight information when the first condition and the second condition are satisfied is “5”, and the sum of the weight information when the first condition and the third condition is satisfied is “4”. The sum of the weighting information when the third condition is satisfied is “3”.

  Therefore, when the two conditions are satisfied, the determination unit 75a sets the pedestrian possibility ranking of the target that satisfies the first condition and the second condition that the sum of the weighting information is “5” as “2”. judge. Further, the determination unit 75a determines that the pedestrian possibility ranking of the target that satisfies the first condition and the third condition for which the sum of the weighting information is “4” is “3”. Further, the determination unit 75a determines that the pedestrian possibility ranking of the target satisfying the second condition and the third condition in which the sum of the weighting information is “3” is “4”.

  In addition, when one of the first condition, the second condition, and the third condition is satisfied, the determination unit 75a similarly satisfies the third condition with the lowest weighting information “1”. The pedestrian possibility ranking of the target is determined as “6”. In addition, the determination unit 75a determines that the pedestrian possibility ranking of the target that satisfies the second condition with the weighting information “2” is “5”. In addition, the determination unit 75a determines that the pedestrian possibility ranking of the target that satisfies the first condition with the highest weighting information “3” is “4”.

  Note that the determination unit 75a determines that the weighting information of the established condition is “3” when the two conditions of the second condition and the third condition are met and when one condition of the first condition is met. Therefore, the pedestrian possibility ranking of the target in both cases is determined to be the same “4”.

  Subsequently, the determination unit 75a outputs the pedestrian possibility ranking of the target detected this time, the estimated angle of the target, the distance, and the relative speed to the adjustment unit 75b. As described above, the determination unit 75a determines the pedestrian possibility ranking of the target based on the weighting information assigned to the established condition when the number of established conditions of the three conditions is the same. The number of pedestrian possibility ranks that can be determined can be increased. Therefore, the determination part 75a can perform more detailed determination of a pedestrian possibility ranking.

  The adjustment unit 75b performs a process of adjusting a predetermined value to be subtracted from the target count value 74d in accordance with the target pedestrian possibility ranking input from the determination unit 75a. When the adjustment unit 75b receives the pedestrian possibility ranking of the target detected this time, the estimated angle of the target, the distance, and the relative speed from the determination unit 75a, first, the adjustment unit 75b outside the detectable area A first. A count value adjustment area for adjusting a predetermined value to be subtracted from the count value 74d is set.

  Here, when the traveling speed of the host vehicle C is relatively high, even a pedestrian who crosses the road on which the host vehicle C travels from a relatively far position in front of the host vehicle C may collide with the host vehicle C. is there. For this reason, when the traveling speed of the host vehicle C is relatively high, the radar apparatus 1 may collide with the host vehicle C in a region from a relatively far position ahead of the host vehicle C to the host vehicle C. It is necessary to detect and track pedestrians.

  On the other hand, when the traveling speed of the host vehicle C is relatively slow, a pedestrian crossing the road on which the host vehicle C travels from a relatively far position ahead of the host vehicle C crosses the road before the host vehicle C passes through. Can be completed.

  For this reason, when the traveling speed of the host vehicle C is relatively slow, the radar apparatus 1 may collide with the host vehicle C in a region from a relatively close position ahead of the host vehicle C to the host vehicle C. If a pedestrian is detected and tracked, a collision between the host vehicle C and the pedestrian can be avoided.

  Therefore, the adjustment unit 75b calculates the traveling speed of the host vehicle C (hereinafter referred to as “own vehicle speed”) based on the estimated angle, distance, and relative speed of the target input from the determination unit 75a. . Then, the adjustment unit 75 b sets a count value adjustment area based on the calculated own vehicle speed and the count value adjustment area information 74 b stored in the storage unit 74.

  The count value adjustment area information 74b is information in which, for each range of the own vehicle speed, the count value adjustment area in which the far limit in the vertical direction is set farther from the own vehicle C as the own vehicle traveling speed is higher. . For example, as shown in FIG. 7A, the own vehicle speed range of 61 to 80 [km / h] is separated from the own vehicle C by 2.4 [m] or more outside the detectable area A, Count value adjustment areas from the vehicle C to the front 15 [m] ahead are associated.

  Further, for example, as shown in FIG. 7B, the vehicle speed range of 31 to 60 [km / h] is separated from the own vehicle C by 2.4 [m] or more outside the detectable area A. The count value adjustment area from the host vehicle C to 10 [m] ahead is associated.

  Further, for example, as shown in FIG. 7C, the vehicle speed range of 0 to 30 [km / h] is separated from the own vehicle C by 2.4 [m] or more outside the detectable area A. The count value adjustment area from the host vehicle C to 5 [m] ahead is associated.

  In addition, the numerical value which prescribes | regulates the range of the own vehicle speed and count value adjustment area which are shown to FIG. 7A-FIG. 7C is an example, and is not limited to this. Further, the count value adjustment area information 74b may include count value adjustment areas respectively associated with the speed ranges of two or less own vehicles, and the count value adjustment areas respectively associated with the speed ranges of four or more own vehicles. May be included.

  The adjustment unit 75b sets a count value adjustment area associated with the range of the own vehicle speed including the calculated own vehicle speed as an area for adjusting a predetermined value to be subtracted from the count value 74d.

  Subsequently, the adjustment unit 75b determines whether or not the target detected outside the currently detectable area A is within the count adjustment area. When the adjustment unit 75b determines that the value is not within the count adjustment area, that is, outside the count adjustment area, the subtraction amount is within a predetermined subtraction value range for a predetermined value to be subtracted from the target count value 74d. The minimum subtraction value “2” is determined. Then, the adjustment unit 75b outputs the determined subtraction value to the count unit 75c.

  Further, when the adjustment unit 75b determines that the target detected outside the currently detectable area is within the count value adjustment area, the adjustment unit 75b subtracts a predetermined value to be subtracted from the count value 74d according to the pedestrian possibility ranking. Make adjustments to the value.

  At this time, the adjustment unit 75b subtracts a predetermined value to be subtracted from the count value 74d based on the target pedestrian possibility ranking input from the determination unit 75a and the count value adjustment information 74c stored in the storage unit 74. adjust.

  As shown in FIG. 8, the count value adjustment information 74c is information in which a pedestrian possibility rank is associated with a subtraction value to be subtracted from the count value 74d. As shown in the figure, in the count value adjustment information 74c, “1” having the highest pedestrian possibility ranking is associated with the subtraction value “2” having the smallest subtraction amount, and the pedestrian possibility ranking is low. The subtraction value whose subtraction amount increases step by step is associated. The subtraction value shown in FIG. 8 is an example.

  When the adjustment unit 75b subtracts the count value of the target in the count value adjustment area, the adjustment unit 75b refers to the count value adjustment information 74c and is associated with the pedestrian possibility ranking of the target input from the determination unit 75a. The subtracted value is determined as a subtracted value to be subtracted from the count value 74d. Then, the adjustment unit 75b outputs the determined subtraction value to the count unit 75c.

  The count unit 75c subtracts the subtraction value input from the adjustment unit 75b from the target count value 74d detected this time. Specifically, the count unit 75c subtracts “2” from the count value 74d when the target is outside the detectable area A and outside the count value adjustment area.

  In addition, when the target is within the count value adjustment area, the count unit 75c “2”, “3”, “4”, “6”, “8” according to the pedestrian possibility ranking of the target. , “9”, “10”, one of the subtraction values is subtracted from the count value 74d.

  As described above, the count value 74d is referred to by an unnecessary target determination unit 73h described later. Then, the unnecessary target determination unit 73h determines that the target whose count value 74d is “0” or less, for example, is an unnecessary target and excludes it from the tracking target.

  Accordingly, the radar device 1 reduces the predetermined value to be subtracted from the count value as the pedestrian possibility ranking increases for the target in the count value adjustment area, It can be continuously tracked for a longer time.

  For example, as shown in FIG. 9, the radar apparatus 1 has a lateral movement speed of 2.3 [km / h] or less, a lateral movement amount of 2.5 [m] or less, and a lateral position variation like a target TG2. For a target (not shown) of 1.0 [m] or more, “10” is sequentially subtracted from the count value 74d in the count value adjustment area.

  As a result, the target TG2 having a low possibility of being a pedestrian has a count value 74d of “35” by the fourth count process even if the count value before entering the count value adjustment area is the upper limit “35”. 0 or less, and is excluded from the tracking target of the radar device 1.

  On the other hand, the radar apparatus 1 has a lateral movement speed of 2.3 [km / h] or more, a lateral movement amount of 2.5 [m] or more, and a lateral position variation (not shown) of 1. For a target of 0 [m] or less, “2” is sequentially subtracted from the count value 74d in the count value adjustment area.

  As a result, the target TG4 having a high possibility of being a pedestrian is finally set to the count value 74d by the 18th count process when the count value before entering the count value adjustment area is the upper limit “35”. It becomes “0” or less, and is excluded from the tracking target of the radar device 1.

  Further, the radar apparatus 1 has a lateral movement speed of less than 2.3 [km / h] as in the target TG3, but the lateral movement amount is 2.5 [m] or more, and the lateral position variation (not shown). For a target of 1.0 [m] or less, “6” is sequentially subtracted from the count value 74d in the count value adjustment area.

  As a result, the target TG3, which has a higher possibility of being a pedestrian than the target TG2, and is less likely to be a pedestrian than the target TG4, has an upper count value before being in the count value adjustment area. In the case of “35”, the radar apparatus 1 becomes a tracking target until the sixth count process.

  Thus, according to the radar apparatus 1, it is possible to continuously track a target that has a high possibility of being a pedestrian for a longer time.

  Moreover, the adjustment unit 75b determines the distance from the own vehicle C to the far limit position in the traveling direction in the count value adjustment area defined outside the detectable area A as an area for adjusting the predetermined value subtracted from the count value 74d. It changes according to the traveling speed of.

  Thereby, for example, when the own vehicle speed is relatively high, the radar apparatus 1 is a pedestrian existing at a position relatively far from the own vehicle C outside the detectable area A where there is a risk of colliding with the own vehicle C. It is possible to make it difficult to exclude a seeming target from the tracking target.

  In addition, the radar device 1 may be a pedestrian that exists at a position relatively close to the own vehicle C outside the detectable area A where there is a risk of collision with the own vehicle C when the own vehicle speed is relatively low. It is possible to make it difficult to exclude the target from the tracking target.

  Returning to the description of FIG. 2, the target classification unit 73g will be described. The target classification unit 73g classifies each target into a moving object (for example, a preceding vehicle, an oncoming vehicle, a pedestrian, etc.) and a stationary object based on the filter processing result of the filter processing unit 73e. The target classification unit 73g outputs the classified classification result to the unnecessary target determination unit 73h.

  The unnecessary target determination unit 73h determines whether or not the target is unnecessary in terms of system control. The unnecessary target determining unit 73h refers to the count value 74d of each target, and determines that the target whose count value 74d is equal to or less than “0” is an unnecessary target. Unnecessary targets are structures, wall reflections, and the like. In addition, although the target made unnecessary is not made into the output object to an external apparatus fundamentally, you may hold | maintain internally. Then, the unnecessary target determination unit 73h outputs information related to the target that is not determined to be unnecessary to the combination processing unit 73i.

  The combination processing unit 73i performs grouping for a target that is estimated to be a reflection point from the same object among a plurality of targets detected as existing, and outputs the grouping result as an output object. It outputs to the mark selection part 73j.

  The output target selection unit 73j selects a target that needs to be output to an external device for system control. In addition, the output target selection unit 73j outputs target information regarding the selected target (including the actual angle, distance, relative speed, etc.) to the external device.

  Here, the external device is, for example, the vehicle control device 10. The vehicle control device 10 is an ECU (Electronic Control Unit) that controls each device of the host vehicle C. The vehicle control device 10 is electrically connected to, for example, a vehicle speed sensor 11, a rudder angle sensor 12, a throttle 13, and a brake 14.

  The vehicle control device 10 performs vehicle control such as ACC (Adaptive Cruise Control) and PCS (Pre-Crash Safety System) based on the target information acquired from the radar device 1.

  For example, when ACC is performed, the vehicle control device 10 uses the target information acquired from the radar device 1 so that the host vehicle C follows the preceding vehicle while keeping the inter-vehicle distance from the preceding vehicle constant. The throttle 13 and the brake 14 are controlled. In addition, the vehicle control device 10 obtains the traveling state of the host vehicle C that changes from time to time, that is, the vehicle speed, the steering angle, and the like from the vehicle speed sensor 11, the steering angle sensor 12, etc., and feeds back to the radar device 1.

  Further, for example, when performing the PCS, the vehicle control device 10 uses the target information acquired from the radar device 1 and there is a preceding vehicle, a stationary object, or the like that has a risk of collision in the traveling direction of the host vehicle C. If this is detected, the brake 14 is controlled to decelerate the host vehicle C. In addition, for example, an alarm device (not shown) is used to warn the passenger of the host vehicle C, or the passenger is fixed to the seat by retracting a seat belt in the passenger compartment.

  Next, a processing procedure executed by the data processing unit 73 of the radar apparatus 1 according to this embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating main processing executed by the data processing unit 73 of the radar apparatus 1 according to the embodiment. FIG. 11 is a flowchart showing the counting process during the main process according to the embodiment.

  As shown in FIG. 10, first, the peak extraction unit 73a performs a peak extraction process based on the beat signal after the fast Fourier transform process input from the FFT unit 72 (step S101). Subsequently, the azimuth calculation unit 73b performs an azimuth calculation process based on the processing result of the peak extraction process (step S102).

  Thereafter, the pairing unit 73c performs a pairing process based on the processing result of the azimuth calculation process (step S103). Subsequently, the continuity determination unit 73d performs a continuity determination process based on the processing result of the pairing process (step S104). Thereafter, the filter processing unit 73e performs a filter process based on the processing result of the continuity determination process (step S105).

  Subsequently, the count processing unit 73f performs count processing for adding or subtracting the count value 74d of each target based on the processing result of the filter processing (step S106). Details of the counting process will be described later with reference to FIG.

  Subsequently, the target classification unit 73g performs target classification processing based on the processing result of the filter processing (step S107). Thereafter, the unnecessary target determination unit 73h performs an unnecessary target determination process based on the processing result of the target classification process (step S108). Then, the combination processing unit 73i performs a combination process based on the processing result of the unnecessary target determination process (step S109).

  Then, the output target selection unit 73j performs output target selection processing based on the processing result of the combination processing (step S110), and outputs the target information of the target selected as the output target to the external device. The process ends.

  Next, the counting process will be described with reference to FIG. The count processing unit 73f repeatedly executes the process shown in FIG. 11 at a predetermined cycle. Specifically, when the processing result of the filter processing is input from the filter processing unit 73e, the count processing unit 73f determines whether the target detected this time is outside the detectable area A (step S201). .

  If the count processing unit 73f determines that it is not outside the detectable area A (step S201, No), the count processing unit 73f adds a certain value (for example, “4”) to the count value 74d of the target detected this time (step “201”). S208), the process is terminated.

  Further, when the count processing unit 73f determines that the target detected this time is outside the detectable area A (step S201, Yes), the count processing unit 73f determines the pedestrian possibility ranking of the target (step S202). Thereafter, the count processing unit 73f sets a count value adjustment area corresponding to the host vehicle speed (step S203).

  Subsequently, the count processing unit 73f determines whether or not the target detected this time is within the count value adjustment area set in step S203 (step S204). If the count processing unit 73f determines that it is within the count value adjustment area (Yes in step S204), the count processing unit 73f determines a predetermined value to be subtracted from the count value 74d as a subtraction value corresponding to the determined pedestrian possibility rank. (Step S205), the process proceeds to step S206.

  If the count processing unit 73f determines that the target detected this time is outside the count value adjustment area (No in step S204), the count processing unit 73f determines the predetermined value to be subtracted from the count value 74d as the minimum value of the subtraction value. (Step S207), the process proceeds to step S206. In step S206, the count processing unit 73f subtracts the determined subtraction value from the count value 74d of the target detected this time, and ends the process.

  The above-described embodiment is an example, and the radar apparatus 1 according to the embodiment can be variously modified. Next, a radar apparatus according to Modification 1 of the embodiment will be described with reference to FIGS.

  In the radar apparatus according to the first modification, in addition to the first condition, the second condition, and the third condition described above, the detected position of the target existing outside the detectable area A matches the predicted movement miracle of the pedestrian. Based on the degree, the pedestrian possibility ranking of the target is determined.

  FIG. 12 is an explanatory diagram illustrating an example of pedestrian condition information stored in the radar device according to the first modification of the embodiment. FIG. 13 is an explanatory diagram of a procedure in which the radar device according to the first modification of the embodiment determines the degree of coincidence between the target position and the predicted movement trajectory of the pedestrian. FIG. 14 is an explanatory diagram illustrating an example of count value adjustment information stored in the radar apparatus according to Modification 1 of the embodiment.

  The radar apparatus according to Modification 1 stores the pedestrian condition information shown in FIG. 12 by the storage unit 74 instead of the pedestrian condition information 74a shown in FIG. 6, and changes to the count value adjustment information 74c shown in FIG. The count value adjustment information shown in FIG. In addition, the radar device according to the first modification stores a plurality of predicted movement trajectories of pedestrians depending on the situation when the pedestrian crosses the traveling direction of the host vehicle C by the storage unit 74.

  Here, the predicted movement trajectory of the pedestrian changes the pedestrian angle with respect to the own vehicle C, the distance from the own vehicle C to the pedestrian, the speed of the own vehicle C, and the lateral movement speed of the pedestrian. However, it is derived by a collision experiment in which the host vehicle C collides with a dummy pedestrian or by acquiring an actual pedestrian trajectory on a trial basis.

  In addition, as shown in FIG. 12, the pedestrian condition information stored in the radar apparatus according to the first modification is predicted movement trajectory for each combination that satisfies the first condition, the second condition, and the third condition. And the pedestrian possibility ranking are associated with each other. Note that the condition contents of the first condition, the second condition, and the third condition, the weighting information related to each condition, and the combination of the conditions are the same as the pedestrian condition information 74a shown in FIG.

  The degree of coincidence with the predicted movement trajectory shown in FIG. 12 is a pedestrian selected from the storage unit 74 according to the own vehicle speed, the lateral movement speed of the target, the angle of the target with respect to the own vehicle C, and the distance. This is the degree of coincidence between the predicted movement trajectory and the detection position of the target existing outside the detectable area A.

  In the example shown in FIG. 12, three levels of coincidence of “high”, “medium”, and “low” are associated with each combination of the first condition, the second condition, and the third condition. In the pedestrian condition information shown in FIG. 12, the pedestrian possibility ranking is associated with each matching degree.

  Further, as shown in FIG. 14, the count value adjustment information stored in the radar apparatus according to the first modification includes subtraction values to be subtracted from the target count value for each pedestrian possibility ranking shown in FIG. It is associated.

  Then, when the detected target is present in the detectable area A, the radar apparatus according to the first modification is based on the information input from the filter processing unit 73e, and the horizontal movement speed and the horizontal The movement amount and the lateral position variation are calculated.

  Furthermore, the radar apparatus according to the modification 1 determines the degree of coincidence between the predicted movement trajectory of the pedestrian selected from the storage unit 74 according to the situation and the detection position of the target existing outside the detectable area A. . At this time, the radar apparatus according to the first modification, for example, is based on the predicted movement trajectory indicated by the hatched square row in FIG. 13 and the detection position of the target TG indicated by the white circle in FIG. Determine.

  Specifically, the radar apparatus according to the modification 1 determines the degree of coincidence once for a predetermined number of times (here, three times) for the detection positions of the same target that are sequentially detected. The radar apparatus according to the modification 1 determines that the degree of coincidence is “high” when all of the three detection positions are located on the predicted movement trajectory among the detection positions of the previous time, the previous time, and the previous time.

  In addition, the radar apparatus according to the first modification determines that the degree of coincidence is “medium” when the two detection positions are located on the predicted movement trajectory among the detection positions of the previous time, the previous time, and the previous time. Further, the radar apparatus according to the modification 1 determines that the degree of coincidence is “low” when one detection position is located on the predicted movement trajectory among the detection positions of the previous time, the previous time, and the previous time.

  The radar apparatus according to the modified example 1 determines a combination in which the first condition, the second condition, and the third condition are satisfied based on the calculated lateral movement speed, lateral movement amount, and lateral position of the target. Further, the degree of coincidence is determined by the procedure shown in FIG.

  Subsequently, the radar apparatus according to Modification 1 refers to the pedestrian condition information illustrated in FIG. 12, and determines the pedestrian possibility ranking associated with the combination of the established conditions and the determined degree of coincidence. It is determined that it is a person possibility ranking. Subsequently, the radar apparatus according to Modification 1 refers to the count value adjustment information illustrated in FIG. 14 and subtracts the subtraction value associated with the determined pedestrian possibility rank from the target count value 74d.

  As described above, the radar apparatus according to the modified example 1 further detects the target detection position in addition to the first condition, the second condition, and the third condition described above as a reference for determining the target pedestrian rank. And the degree of coincidence between the predicted movement trajectory of the pedestrian and the pedestrian.

  Thereby, since the radar apparatus according to the modification 1 can further subdivide the pedestrian possibility ranking, it is possible to more accurately determine the high possibility that the target is a pedestrian. Therefore, the radar apparatus according to the modified example 1 can continuously track a target that is likely to be an accurately determined pedestrian for a longer time.

  Note that the radar apparatus according to the embodiment does not consider the first condition, the second condition, and the third condition described above, based on the degree of coincidence between the target detection position and the predicted movement trajectory of the pedestrian, The structure which determines the pedestrian possibility ranking of a target may be sufficient.

  In the case of such a configuration, for example, the radar apparatus according to the second modification of the embodiment includes a plurality of predicted movement trajectories of pedestrians that differ depending on the situation when the pedestrian crosses the traveling direction of the host vehicle C described above, The pedestrian condition information shown in FIG. FIG. 15 is an explanatory diagram illustrating an example of pedestrian condition information stored in the radar device according to the second modification of the embodiment.

  As illustrated in FIG. 15, in the pedestrian condition information stored in the radar device according to the second modification, the degree of coincidence between the target detection position and the predicted movement trajectory of the pedestrian is associated with the pedestrian possibility ranking. It is done. In the example shown in the figure, the degree of coincidence between 0 and 100 [%] is divided into 10 steps in increments of 10 [%]. And the pedestrian possibility ranking from 1 to 10 in order from the one with the highest matching degree is associated with the matching degree at each stage.

  The radar apparatus according to the second modification, for example, is based on the deviation amount of the detected target position from the predicted movement locus (the distance in the horizontal direction between the predicted movement locus and the target position), and the matching rate [%] Is calculated. For example, when the target is located on the movement prediction trajectory, the radar apparatus according to the modification 2 calculates a coincidence rate of 100 [%], and the lateral distance between the prediction movement trajectory and the target position. Is equal to or greater than a predetermined distance, a coincidence rate of 0 [%] is calculated.

  Subsequently, the radar device according to the modified example 2 refers to the pedestrian condition information and sets the pedestrian possibility ranking associated with the degree of coincidence including the calculated coincidence rate [%] to the pedestrian possibility of the target. Judge as rank. And the radar apparatus which concerns on the modification 2 subtracts a small subtraction value from the count value 74d of a target, so that the determined pedestrian possibility ranking is high.

  As described above, the radar apparatus according to the modified example 2 also determines the pedestrian possibility ranking of the target based on the degree of coincidence between the target detection position and the predicted movement trajectory of the pedestrian. Can be tracked for a longer time.

  In the above-described embodiment, the number of the transmission antennas 4 of the radar apparatus 1 is one and the number of the reception antennas 5 is n. However, this is only an example, and a plurality of targets can be detected. Other numbers may be used.

  In the above-described embodiment, ESPRIT is given as an example of the direction-of-arrival estimation method used by the radar apparatus 1. However, the present invention is not limited to this. For example, DBF (Digital Beam Forming), PRISM (Propagator method based on an Improved Spatial-smoothing Matrix), MUSIC (Multiple Signal Classification), or the like may be used.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Radar apparatus 2 Transmission part 4 Transmission antenna 5 Reception antenna 6 Reception part 7 Signal processing apparatus 10 Vehicle control apparatus 11 Vehicle speed sensor 12 Steering angle sensor 13 Throttle 14 Brake 21 Signal generation part 22 Oscillator 61 Mixer 62 A / D conversion part 71 Transmission / reception Control unit 72 FFT unit 73 Data processing unit 73a Peak extraction unit 73b Direction calculation unit 73c Pairing unit 73d Continuity determination unit 73e Filter processing unit 73f Count processing unit 73g Target classification unit 73h Unnecessary target determination unit 73i Combined processing unit 73j Output target selection unit 74 Storage unit 74a Pedestrian condition information 74b Count value adjustment area information 74c Count value adjustment information 74d Count value 75a Judgment unit 75b Adjustment unit 75c Count unit A Detectable area C Own vehicle

Claims (7)

A detection unit that repeatedly performs a detection process for detecting a target approaching the host vehicle;
An extrapolation unit that performs an extrapolation process for predicting a virtual position of the target that is no longer detected in the current detection process based on the target detected in the previous detection process;
Each time the target is detected by the detection process, a fixed value is added to the count value indicating the high possibility that the target exists, and the virtual position of the target is predicted by the extrapolation process. A count unit that subtracts a predetermined value from the count value of the target,
Based on the lateral movement speed of the target existing outside the predetermined angle range with respect to the traveling direction of the own vehicle relative to the own vehicle, the lateral movement amount, and the lateral position variation. A determination unit for determining a high possibility that the mark is a pedestrian;
A radar apparatus comprising: an adjustment unit that adjusts the predetermined value to be subtracted from the count value of the target in accordance with the high possibility determined by the determination unit. The determination unit
A first condition that the lateral movement speed is greater than or equal to a first threshold, a second condition that the amount of lateral movement is greater than or equal to a second threshold, and a third condition that the positional variation in the lateral direction is less than or equal to a third threshold. The greater the number of conditions established, the higher the possibility,
The adjustment unit is
The radar apparatus according to claim 1, wherein the predetermined value to be subtracted from the count value of the target is decreased as the target having the higher possibility determined by the determination unit. The first condition, the second condition, and the third condition are:
Each is assigned weighting information with a different level of importance,
The determination unit
Determining the high possibility based on the weighting information assigned to the established condition among the first condition, the second condition, and the third condition when the number of established conditions is the same; The radar apparatus according to claim 2. The weighting information is
The radar apparatus according to claim 3, wherein the radar apparatus is assigned in the order of the first condition, the second condition, and the third condition in descending order of importance. The adjustment unit is
The distance from the own vehicle to the far limit position in the traveling direction of the count value adjustment area defined outside the predetermined angle range as an area for adjusting the predetermined value to be subtracted from the count value depends on the traveling speed of the own vehicle. The radar apparatus according to any one of claims 1 to 4, wherein the radar apparatus is changed. A storage unit for storing a plurality of predicted movement trajectories of the pedestrian that vary depending on a situation when the pedestrian crosses the traveling direction;
The determination unit
The degree of possibility is determined based on a degree of coincidence between a position of a target existing outside the predetermined angle range and the predicted movement trajectory stored by the storage unit. The radar apparatus according to any one of? A target detection method executed by a computer,
A detection process for repeatedly performing a detection process for detecting a target approaching the host vehicle;
An extrapolation step of performing an extrapolation process for predicting the virtual position of the target that is no longer detected in the current detection process based on the target detected in the previous detection process;
Each time the target is detected by the detection process, a fixed value is added to the count value indicating the high possibility that the target exists, and the virtual position of the target is predicted by the extrapolation process. Each time, a counting step of subtracting a predetermined value from the count value of the target,
Based on the lateral movement speed of the target existing outside the predetermined angle range with respect to the traveling direction of the own vehicle relative to the own vehicle, the lateral movement amount, and the lateral position variation. A determination step of determining a high possibility that the mark is a pedestrian;
An adjustment step of adjusting the predetermined value to be subtracted from the count value of the target according to the high possibility determined by the determination step.

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